Creating SqrlUtil class to hold commonly used code.

Was looking through the code and noticed some duplication around loading the configuration file that could be reduced. Created a util class with a static method to load the file from disk and check it is JSON.

Updated the classes that were loading the configuration to use this utility method instead. Also, where these classes were exposing `loadConfigFromJSON()`, I changed them to instead expose `configure()`. I feel like this will future proof the library in case it moves from using JSON for config to something like YAML. Implementers will only have to update the file name and format of their config file and not have to worry about updating method names behind the scenes.